Educational device



Feb. 10, 1942. R. B. JOHNSON 2,272,410

EDUCATIONAL DEVICE Original Filed June; 21, 1938 18 Sheets-Sheet 1KAY/5701? a/v/r .zaa'rak wwr SEA/SING 42 FIG. 1. 1 M 15 A 93 we INVENTOR1 W ATTORNEY l8 Sheets-Sheet 2 Em: m5. H

R. B. JOHNSON EDUCATIONAL DEVICE Original Filed June 21, 1938 MM'MMIHIMMHMMHIIMHHM 525: w 8 z s 4 Feb. 10, 1942 ATOTRNEY R. B. JOHNSON2,272,410

EDUCATIONAL DEVICE Original Filed June 21, 1938 18 Sheets-Sheet 3 Feb.10, 1942.

Feb. 10, 1942. R. B. JOHNSON EDUCATIONAL DEVICE Original Filed June 21,1938 18 Sheets-Sheet 4 ATTORNEY Feb. 10, 1942.

R. B. JOHNSON 2,272,410

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EDUCATIONAL DEVICE Original Filed June 21, 1938 18 Sheets-Sheet '7 FIG.9.

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EDUCATIONAL DEVICE Original Filed June 21, 1938 l8 Sheets-Sheet 8 a6 5KK INVENTO| ATTORNEY Feb. 10, 1942.

PldT/Z MIRA R. B JOHNSON EDUCATIONAL DEVICE Original Filed June 21, 195818 SheetS Sh'eet l0 ATTRNEY Feb. 10,- 1942. R. B. JOHNSON 2,272,410

EDUCA'I' IONAL DEVI GE Original Filed June 21, 1938 18 Sheets-Sheet llATT oRNEY Feb. 10, 1942. R. B. JOHNSON 2,272,410

EDUCATIONAL DEVICE Original Filed June 21, 1958 18 Sheets-Sheet 12INVENTR ATTCRN EY Feb. 10, 1942.

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EDUCATIONAL DEVICE Original Filed June 21, 1938 l8 Sheets-Sheet 14 8' gR W a5 Y v LI. ATTORNEY Feb. 10, 1942. R. B. JOHNSON 2,272,410

' EDUCATIONAL DEVICE Original Filed June 21, 1958 18 Shets-Sheet l n 150E 146 r f V 113 :04 h 143 I18 4 we 169 I43 -21 o7 :73 163 I93 we m IH|I"I 1" I 37 n9 I7 I 6 H5 ATTORNEY Feb. 10, 1942. R. B. JOHNSON2,272,410

- EDUCATIONAL DEVICE I Original Filed June 21, 1938 1a Shets-Sheet 16 an/sI/r/ FIG.23.

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' ATT'ORNEY Feb. 10, 1942. R. B. JOHNSON 2,272,410

EDUCATIONAL DEVICE I I Origifial Filed June 21, 1938 1a Sheets-Sheet l8Flt-3.235. 7

AT'i'oRNEY Patented Feb. 10, 1.942

Reynold B.

Johnson, Bingliamton, N. 1h, assignor to International Business Machines Corporation, New York, N. Y., a corporation or New York Original214,922.

application June 21, 1938, Serial No.

Divided and this application Novemher 7, 1940, Serial No. 364,653

Serial No.'214,922, flled June 21', 1938, which relates to a machine forelectrically grading response sheets upon which an examinee hasdesignated responses by means pencil marks. The machine constitutesimprovements over the machine shown in my Patent No. 2,113,620, grantedApril 12, 1938.

The main object of the invention is to extend the usefulness of amachine operating according to the principles 0! my former arrangement,especially in the handling .01? objective tests of, the multiple-choiceor true-false type, the responses to which may be recorded by makingarecord in one of several positions on a response sheet. The

machine is designed to handle. response sheets having a maximum capacityon each side 01 150 five-choice, 300 two-choice or 750 single-choicequestions. In other words, the response sheet has 750 possible markingpositions tobe identifled or numbered to correspond to questions givenorally or contained in asep'arate question.

sheet or booklet or-may be printed on the answer.

. (c1. 22.5-61. This application is a division of application in serieswith each contact unit a high resistance current limiting resistor whichpermits only --a unit amount of current to flow into a meter circuitirom each pencil mark.

The machine distinguishes betweenright and wrong answers by means of aperforated key sheet which blade units into two groups, wrong. From thisdivision, two meter circuits result, one carrying the aggregate oithe'units oi current from the correct and the other carrying theaggregate of responses The machine may be variously set, by 'means ofvarious switching devices, to score in terms 1 of the number right byrouting the current irom sheet. Once the examinee decides which choice 1is the correct answer tor a particulaiiquestion, he merely makes a heavyshort line onthe re.-

spouse sheet in the number space corresponding to the number of hischosenanswer.

The functioning of the machine depends on the fact that a soft leadpencil orspecial ink mark is electrically conductive and that the 01'current flowing through each pencil or ink mark may be controlled andkept to a uniform unit,

whether the mark is very heavy or relatively light.

When the response sheet is inserted in the machine, it is pressedagainst a contact plate containing 750 sets of sensing bladescorresponding to the 750 response positions on the response sheet. Thesesets of sensing blades consist each oi-flve small parallel metal bladeswhich are con-- nected alternately to the positive and negative sides oithe circuit. Whenever a pencil mark is pressed against one of the setsof sensingblades, it closes the electric gap between the positive andnegative blades and a through the circuit. 11! pencil marks are pressedagainst ten of the sets 0! contact blades, ten units of current flowthrough-the circuit. It a pencil mark is sufilciently long, it willbridge the electric gap four times; it the pencilmarkis very short, itwill bridge the gap only once, but in either case the unit of currentflowing through the circuit from the pencil-mark-bridge remainspractically the rights circuit through a large milliammeter.

This meter is ordinarily calibrated directly in terms of the unit 01current'flowing through the meter from each small circuit and hence the.

reading on .the meter is equal to the number 01 right responses on theagainst the sensing. blades. The score indicated on the metals recordedbythe operator. on the exposed margin oi" the response sheet oron aseparate record sheet or the'operator may call thesco'reto a recordingclerk, s

It the score is in terms of the number wrong, the current from thewrongs circuit is routed through the'meter which indicates to theoperator the number wrong.

, It the score is in terms 01 irights" minus fwrongs," the the oppositeside of wrongs circuit is connected to the meter from the rightscircuit, so thatthe meter reading is the Menence between the twocurrents, thus registering the "rights minus the wrongs.

unit 01. current flows doingthis The machine may be adjusted toobtainthe I score in terms voi! the rights minus one-half the wrongs, in"which case-one-hali of the current from the wrongs ordinarily flowingthrough the meter is shunted past the meter and thus the scoreregistered is the rights minus one-half the wrongs. Similarly, the scorecan be obtained in termsoi the rights minus any fraction of the wrongs.

The machine may may carry a value of more than 1. In the applied voltageis' increased, so that the .cu'rrent flowing through any responsecircuit may be greater than flows ordinarily.

' constant. This result is'achieved by connecting as score of 100. ThisIf a test or .77 items, for example, is scored in terms oi. percentage,the voltage is stepped up so that a score 01V 77 is indicated on themeter as a automatically divides the sensing the right and the the unitsof current from the incorrect responses.

answer sheet being pressed be adjusted sothat each re- Y I is equivalentto multiplying each score by 1.298. With such setting, the responsesheets are scored directly in terms of the percentage of rights, thepercentage of wrongs or the percentage of rights minus the percentage ofor some fraction of the wrongs. If the machine is adjusted so that thescore is in terms of rights minus twice the wrongs, the voltage isdoubled for all responses, but one-half of the current from the rightresponses ordinarily flowing through the meter is shunted past themeter. Hence, the current resulting from each right response moves themeter needle up one point and the current resulting from each wrongresponse moves the meter down two points.

The machine has three sets of controls which makes it possible to scorewith one insertion of the response sheet three difierent tests or threedifierent parts of one test, and each test can be scored by any formulain terms of rights and wrongs. The machine is further provided with anegative score key which reverses the meter connections so that currentwhich ordinarily causes the meter to deflect below will cause it todeflect above 0. This key is utilized in such cases where the machine isset to score a number of rights minus wrongs and the number of wrongs isgreater. 7

The present invention deals with a so-called aggregate weighting unit,which may be inserted in the machine for cooperation with the sensingdevices and meter circuit connections. With this unit it is possible tocompute weighted averages of as many as thirty measures with weightsranging from 1 to 20.

The record sheet upon which the measures to be Weighted are recorded isdivided into 30 areas, each containing 20 positions, for the tensdigitand 10 for the units digit. The measures to be averaged arerecorded in these areas by drawing a pencil line. through the positionscorresponding to the number, that is, for a grade of 75 a line would bedrawn through the first 7 tens digit positions and a second line throughthe first 5 of the units digit positions. The measures are weighted byplacing each of ten contacting jacks on the weighting unit in one ofpossible weight positions. With this unit in position in the machine andthe record sheet inserted and placed in contact with the sensing pins,the meter will indicate the weighted average of the measures recorded onthe sheet.

Other objects of the invention will be pointed out in the followingdescription and claims and illustrated in the accompanying drawings,which disclose, by way of example, the principle of the v invention andthe best mode, which has been,

contemplated, of applying that principle.

In the drawings:

Fig. -1 is a front view of the machine with the casing partially brokenaway to show the interior construction.

Fig. 2 is a plan view of the machine with the score indicator and partof the casing removed.

Fig. 2a is a detailof the operating key connections.

Fig. 3 is an enlarged section taken substantially along lines 33 of Fig.2.

Fig. 4 is aview similar to Fig. 3 with the parts in moved or responsesheet sensing position.

Fig. 5 is a specimen of a response sheet marked in accordance with anexaminees selections.

Fig. 6 is a specimen of a, record marked to represent a plurality ofdifferent measures whose average is to be obtained by the machine.

Fig. 7 is a specimen of the main key sheet perthe key sheet holder andthe manner in which the key sheets control the positioning of variouspins.

The section is taken substantially along the lines Ill-40 of Fig. 9.

Fig. 10a is a similar view taken at another section of the holder., InFig. 10a the section is taken substantially along Illa-10a of Fig. '9.

Fig. 11 is a view showing the aggregate score plugboard.

Fig. 11a is a detail cross-section of an aggregate score plugboard jack.

Fig. 12 is a section taken substantially along the lines I2l2 of Fig.11, showing the relationship between the plugboard and the key sheet pinunit.

Fig. 13 is a plan section taken substantially along the lines |3-I3 ofFig. 12.

Fig. 14 is an isometric view showing the manner in which the aggregatescore plugboard is inserted in the machine.

Fig. 15 is a detail view of the response sheet sensing unit.

Fig. 16 is a plan view of the unit broken away to show the interiorconstruction.

Fig. 17 is an enlarged detail of one of the sensing devices shown inFig. 16.

Fig. 17a is a detail showing a modified arrangement enabling the sensingblades to read marks made in the form of perforations.

Fig. 18 is a detail of the resistor panel.

Fig. 19 is an enlarged detail of Fig. 18 taken substantially along thelines 19-19 of Fig. 18.

Fig. 20 is a detail view showing the key sheet pin unit and the mannerin which it is supported in the machine.

Fig. 21 is a sectional view taken substantially along lines 2I-2l ofFig. 3.

Response sheet The response sheet R upon which the examinee records hisselections is shown in Fig. 5. The sheet is provided with 25 verticalcolumns arranged in groups of five and each group of five is separatedvertically into two fifteen-line fields, one or more of which may begrouped together to constitute a single test. Each response designatingposition RI is delineated by a pair of vertical parallel lines betweenwhich the examinee is to draw a heavy black line R2 with a pencil or pencoextensive with the parallel lines. Thus, for example, if the firstquestion on an examination required the selection of one of fivepossible answers and if the examinee selected

